Field of the Invention
The invention relates to a method for disposing of a component located in a reactor pressure vessel of a nuclear reactor plant.
While a nuclear reactor plant is in operation, damage to plant parts or components may occur, making it necessary to exchange those components. The old components then have to be removed and disposed of. Particularly in the case of components of the primary circuit of the nuclear reactor plant, it is necessary to accommodate the removed components in a shielded container that is suitable for further transport. Due to the radioactively contaminated surfaces, those tasks, that is to say the removal of the old component and the transfer of the latter into the shielded container, subject the operating personnel to a considerable dose of radiation. That occurs particularly in the case of large-volume components which are installed in a reactor pressure vessel in the vicinity of the fuel assemblies. Such components are, for example, a lower core structure installed in the reactor pressure vessel of a pressurized water reactor plant in order to receive the fuel assemblies.
German Published, Non-Prosecuted Patent Application DE 36 26 207 A1, corresponding to U.S. Pat. No. 4,696,786, discloses a method for exchanging internal fittings of a reactor pressure vessel. In that method, a prefabricated large-volume component made ready next to the reactor pressure vessel is inserted into the water-flooded reactor pressure vessel and fitted in. The removal of the radioactively contaminated old or spent component is not described in any more detail in those publications. They merely explain that, in order to take that component out of the reactor pressure vessel, the reactor well, in which the reactor pressure vessel is located, is previously flooded with water.